Download Routing on the Edge of Fragile Meshed Networks

OSPF for Broadband Wireless
Campus Backbone
Joseph Hui
ISS Chair Professor and Director,
Telecommunications Research Center
Arizona State University
Talk Outline
• Applications for Wireless Broadband
Campus Networks
• Optical versus Radio Frequency
• OSPF for Broadband Wireless Networks
• On-going embedded system prototype.
Applications of Broadband
Wireless Backbone
• Large data storage facilities scattered on campus
• Growing need for multimedia educational
material storage/retrieval
• Digital/video libraries
• Massive data stores (Mars Probe, 3D models)
• Wireless LAN hot spots
• Portable wireless multimedia booths?
ASU Campus Backbone
•
•
•
•
•
•
Hub and Spoke Gigabit Ethernet.
Three level hierarchical network
East-Central-West Campus
A few isolated, off-campus buildings
Want: Scalable and reconfigurable networks
Solutions:
– Wireless broadband
– Distributed Storage Area Networks
– Reliable OSPF protocol for wireless links
ASU BACKBONE NETWORK 2000
ASU WEST
ASU EAST
SD
Power Supply 1
SD
Power Supply 2
Power Supply 1
POWER
115/230 VAC
9.8/4.9 A
60/50Hz
Power Supply 2
POWER
115/230 VAC
9.8/4.9 A
60/50Hz
10MB ETHERNET
10MB ETHERNET
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Internet 2
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Internet 1
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Internet 1
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155Mbps
OLD MAIN
ASUW-gw
Layer 3
Etherswitch
155Mbps
ASUE-gw
Layer 3
Etherswitch
MAIN-gw
Layer 3 Etherswitch
SD
Power Supply 1
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POWER
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BUILDING 1 100 MB
BUILDING 2
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BUILDING N
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ROUTER
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ROUTER
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1GB
SD
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POWER
115/230 VAC
9.8/4.9 A
60/50Hz
LAYER 2
ETHERSWITCH
NAU, UofA
AND ASPIN
CUSTOMERS
LEASED LINE
AND
FRAME RELAY
CONNECTIONS
DMZ
ROUTER
Power Supply 2
POWER
115/230 VAC
9.8/4.9 A
60/50Hz
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LAYER 2
ETHERSWITCH
1GB
BAC
ECA
SD
Power Supply 1
BUILDING 1
100MB
BUILDING 2
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100MB
BUILDING N
SD
Power Supply 2
Power Supply 1
POWER
115/230 VAC
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60/50Hz
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1GB
1GB
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100MB
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BAC113-gw
ECA141B-gw
Layer 3
Etherswitch
Layer 3
Etherswitch
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Power Supply 1
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60/50Hz
COMPUTING
COMMONS
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BUILDING 1
BUILDING 2
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100MB
BUILDING N
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CPCOM-gw
Layer 3
Etherswitch
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TYPICAL CAMPUS BUILDING
100MB
Catalyst 2900
SYSTEM
SERIES XL
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WorkStation
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Etherswitch
WorkStation
RPS
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GOLDWATER
10MB ETHERNET
May 15, 2001
Power Supply 2
POWER
115/230 VAC
9.8/4.9 A
60/50Hz
100MB ETHERNET
WorkStation
ASU
INFORMATION
TECHNOLOGY
SERVER
FARM
TYPICAL CAMPUS BUILDING
100MB
100MB
Building IDF N
Layer 2 Etherswitch
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green = enabled link OK
flashing green = disabled
off = no link
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partition
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STACK 
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off = no traffic
green = traffic
yellow = collision
10 11 12
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Power/Self test
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Stack/Attn
100MB
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3Com
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Port Switch
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Building. IDF 3
Layer 2 Shared
Ethernet Concentrator
10MB
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100MB
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Building IDF 3
Layer 2 Etherswitch
100MB
1x
6x 13
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Status
green = enabled link OK
flashing green = disabled
off = no link
MDI
MDIX 1
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yellow =
partition
SUPER
STACK 
Segment
off = no traffic
green = traffic
yellow = collision
10 11 12
Tcvr1
Seg1
Seg2
Power/Self test
13 14 15 16 17 18 19 20 21 22 23 24
Tcvr2
Seg3
Seg4
Stack/Attn
SD
3Com
Super Stack II
Port Switch
10MB
10MB
Building IDF 2
Layer 2 Etherswitch
100MB
1x
6x 13
18x
7x
12x19x
24x
Status
green = enabled link OK
flashing green = disabled
off = no link
MDI
MDIX 1
2
3
4
5
6
7
8
9
yellow =
partition
SUPER
STACK 
Segment
off = no traffic
green = traffic
yellow = collision
10 11 12
Tcvr1
Seg1
Seg2
Power/Self test
13 14 15 16 17 18 19 20 21 22 23 24
Tcvr2
Seg3
Seg4
Stack/Attn
USER 1
USER 2
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USER N
USER 1
USER 2
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10MB
100 MB
CONNECTIVITY
FROM ASU
BACKBONE
Layer 3
Etherswitch
USER 1
USER 2
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USER N
SD
3Com
Super Stack II
Port Switch
10MB
10MB
Building MDF
Layer 2 Etherswitch
Catalyst 1900 Series SD
CISCO SYSTEMS
10BaseT
SYSTEM
May 16, 2001
RPS
STAT UTL FDUP
MODE
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Building IDF 1
Layer 2 Etherswitch
Proposed Broadband Wireless
Network Topology
• An adjunct broadband wireless network
• Mesh/Ring network for the second tier hubs
• Mesh/relay network for third tier nodes
Optical versus Radio Networks
• Advantages of optics:
–
–
–
–
–
–
No spectrum licensing
No multipath problems
Cheaper/smaller transceivers
high speed/DWDM
Excellent channel isolation
Security
• Advantages of radio:
–
–
–
–
–
–
LOS not mandatory
Longer distances
More weather resistant
Less background noise
Ease of pointing
Eye safe
Going Optical
Wireless Campus Network
• Current approaches
– LMDS for WLL, not
backbone
– Hub architecture
– Shared bandwidth
– LEC model
– DSL over ATM
• Proposed Approach:
– Totally wireless backbone, no
distinguishable local loops.
– Mesh architecture
– Multiple parallel paths
– Internet model
– {SCSI,FC,10xBaseT,TCP,IB}
over IP
Key Challenges
• Optical links
– propagation, pointing, power budget, eye safety
• Data links
– link/node failure, traffic measurements, QoS control
• Network routing/management
– Ad-hoc routing, IP switching, resource discovery,
traffic balancing, domain management
• System Analysis
– Interface interoperability, multiple protocols, device
mapping/configurations.
Network Types
• Meshed Networks
– Fully Meshed (Each
and every node is
connected to all others
by no more than one
hop)
– Partially Meshed (A
node may be connected
to other nodes by more
than one hop)
• Fragile Networks
– Any link of the
network may become
inoperative at any time.
The failure of a single
link should not prohibit
message delivery
The Effect of Fragility
(Providing A High Availability Environment)
1.
Router Failure
2.
CPE Failure
3.
Premise Link Failure
4.
Link Failure
Protocols for Wireless Optical
Ad-Hoc Networks
1.
2.
3.
4.
5.
Link-state monitoring
QoS provisioning
Rapid yet distributed rerouting upon link/node failure
Resource discovery and management
Multi-protocol adaptations
Reliable IP based on OSPF
• OSPF is the predominant IP protocol for
– Intra-domain, distributed, link-state based routing
– Problem: rerouting require broadcast of link-state
• To make OSPF reliable
– QoS control based on DiffServ, TOS queue scheduling
– Pre-compute multiple paths based on QoS and link failure
– Rapid switch over to source routing if link or node fails
• Problem: Is it possible to retain much of OSPF distributed
computation, yet able to route correctly when link/node fails?
Reliable IP based on OSPF
• Answer is Yes!
• Multipath OSPF with IP-encapsulation for source routing
• Node broadcasts link state infrequently
– Each node compute multiple paths contingent on fault/QoS
– Multiple IP for QoS assignments
– Use of IP encapsulation to forward packets along
precomputed path.
Experimental Prototypes
• The Existing Project
– Pizza box Router for Network Edge use based on IP
– Free Space Laser Link at 850 nm and 1Gb/s
– Millimeter Wave RF Link at 57-64 GHz and 1 Gb/s
• Applied both indoor and outdoor
Conclusion
• Distributed Router Development
– Protocol (Reliable IP)
– QoS Routing and QoS Link Management
– Network Management (IP encapsulation)
– Mirroring and Multicasting
• Four link implementations at 1 GHz
– Free Space Laser
– Wireless Millimeter Wave
– Fiber optic
– Copper
• Currently soliciting public and private funding for prototype